After a nearly four-month long air campaign over England, Britain's Royal Air Force and Navy respond to heavy bombing attacks from Germany's Luftwaffe air force, including “the Blitz,” which was an attempt to destroy the RAF before invading. Defense systems, such as radars, and Hitler's decision to bomb London, rather than military bases, allowed Britain to regroup and eventually win the battle.

American, British and Canadian troops stormed five beaches at Normandy, France on June 6, 1944. This event came to be known as D-Day, being one of largest water invasions in military history. At Omaha Beach, America suffered more than 2,000 American casualties and some 4,000 deaths that day. But by June 11, the beaches were secured and 325,000-plus forces landed. The Allies began their advance across Normandy, eventually liberating Paris.